Study on op*cal levita*on of a mg-scale mirror ( - - PowerPoint PPT Presentation

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Study on op*cal levita*on of a mg-scale mirror ( - - PowerPoint PPT Presentation

Oct 17, 2022 346 likes •747 views

Study on op*cal levita*on of a mg-scale mirror ( ) UTokyo, KAGRA Observatory, ICRR Koji Nagano ( ) (With a lot of support from Shotaro Wada, Takuya Kawasaki, Yuta Michimura,

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Study on op*cal levita*on of a mg-scale mirror (光輻射圧による鏡の光学浮上技術の開発)

UTokyo, KAGRA Observatory, ICRR

Koji Nagano (長野 晃士) (With a lot of support from Shotaro Wada, Takuya Kawasaki, Yuta Michimura, Takafumi Ushiba, Nobuyuki Matsumoto, and Masaki Ando)

ICRR GW group seminar (Nov. 9th, 2017) 1

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ICRR GW group seminar (Nov. 9th, 2017) 2

  • NAGANO Koji (D1)
  • Mainly in Hongo campus (table top).
  • Study topics

– Gravita*onal wave detector

  • Input-output op*cs (IOO)
  • Main interferometer (MIF)

– Opto-mechnical system – Macroscopic quantum mechanics

Self introduc*on

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ICRR GW group seminar (Nov. 9th, 2017) 3

  • We are studying quantum noise in the

gravita*onal wave detector and macroscopic quantum mechanics.

  • For these studies, interferometer which is

dominated by quantum effect should be prepared although it can be hidden easily by environmental (classical) disturbance.

  • To avoid environmental disturbance induced

by ordinary mechanical suspension system, we proposed new technique, op*cal levita*on of the mirror.

  • In this talk, op*cal levita*on will be

introduced and current experimental status will be reported.

Abstract

Schema*c of

  • p*cal levita*on.
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ICRR GW group seminar (Nov. 9th, 2017) 4

  • 1. Introduc*on
  • 2. Op*cal Levita*on
  • 3. Current status
  • 4. Summary

Outline

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SLIDE 5

ICRR GW group seminar (Nov. 9th, 2017) 5

  • 1. Introduc*on
  • 2. Op*cal Levita*on
  • 3. Current status
  • 4. Summary

Outline

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ICRR GW group seminar (Nov. 9th, 2017) 6

  • Laser interferometer is a very

precise posi*on measurement device and used to detect gravita*onal waves.

  • One of the major noise sources
  • f the interferometers is

quantum fluctua*on of light.

  • Thus, we need to know the

features of the quantum mechanics (QM) deeply to reduce the quantum noise (QN) and improve the sensi*vity of interferometers.

Introduc*on

Michelson interferometer. (Made by S. Kawamura)

Frequency [Hz] Strain [/rtHz] KAGRA latest es*mated sensi*vity. Quantum noise

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ICRR GW group seminar (Nov. 9th, 2017) 7

  • In addi*on, this QN study leads to answer to
  • ne the most fundamental ques*on of physics:

“In the macroscopic world, does quantum mechanics hold?”

  • Surprisingly, we cannot answer this ques*on

although QM is successful in the microscopic world, such as electrons, atoms, and so on.

Introduc*on

e-

electrons (micro) apples (macro) screen double slit

???????

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ICRR GW group seminar (Nov. 9th, 2017) 8

  • In the macroscopic world, we have not

seen quantum effect, such as super posi*on.

  • Is this because,

– Just classical noise (CN) is large? – We need macroscopic quantum mechanics?

  • To confirm the situa*on, we should

make various mass-scale systems which is dominated by quantum effect.

  • This is also necessary for the

development of the reduc4on technique of QN of GW detectors.

Introduc*on

???????

Deeply related!!

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ICRR GW group seminar (Nov. 9th, 2017) 9

  • Prior works

Introduc*on

membrane, 48 pg, Teufel+ (2011) nanomechanical

  • scillator, 311 fg,

Chan+ (2011) membrane, 7 ng, Peterson+ (2016) suspended mirror, 5 mg, Matsumoto+ (2014) suspended mirror, 1 g, Neben+ (2012) suspended mirror, 23--40 kg, GW detector (aLIGO, AdV, KAGRA)

mass fg pg ng ug mg g kg

Planck mass (~ 22 ug)

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ICRR GW group seminar (Nov. 9th, 2017) 10

  • Prior works

Introduc*on

membrane, 48 pg, Teufel+ (2011) nanomechanical

  • scillator, 311 fg,

Chan+ (2011) membrane, 7 ng, Peterson+ (2016) suspended mirror, 5 mg, Matsumoto+ (2014) suspended mirror, 1 g, Neben+ (2012) suspended mirror, 23--40 kg, GW detector (aLIGO, AdV, KAGRA)

mass fg pg ng ug mg g kg

Planck mass (~ 22 ug)

QN dominant QN dominant QN dominant Almost QN dominant CN dominant CN dominant

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ICRR GW group seminar (Nov. 9th, 2017) 11

  • Prior works

Introduc*on

membrane, 48 pg, Teufel+ (2011) nanomechanical

  • scillator, 311 fg,

Chan+ (2011) membrane, 7 ng, Peterson+ (2016) suspended mirror, 5 mg, Matsumoto+ (2014) suspended mirror, 1 g, Neben+ (2012) suspended mirror, 23--40 kg, GW detector (aLIGO, AdV, KAGRA)

mass fg pg ng ug mg g kg

Planck mass (~ 22 ug)

QN dominant QN dominant QN dominant Almost QN dominant CN dominant CN dominant

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ICRR GW group seminar (Nov. 9th, 2017) 12

  • 1. Introduc*on
  • 2. Op*cal Levita*on
  • 3. Current status
  • 4. Summary

Outline

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ICRR GW group seminar (Nov. 9th, 2017) 13

Op*cal levita*on

  • Suspension system (for seismic isola*on) may

introduce addi*onal classical thermal disturbance and can hide quantum effect.

  • To avoid the thermal effect, new technique to

support mirror using only op*cal radia*on which is called as op*cal levita*on was proposed.

fluctua*on gravity gravity radia*on pressure tension

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ICRR GW group seminar (Nov. 9th, 2017) 14

Op*cal levita*on

Study quantum noise in interferometers Test of macroscopic quantum mechanics Improve sensi*vity of gravita*onal wave detectors Isolate the system from the environment and make the system dominated by quantum effect

Levitate the mirror only by op4cal radia4on pressure

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ICRR GW group seminar (Nov. 9th, 2017) 15

Op*cal levita*on

Study quantum noise in interferometers Test of macroscopic quantum mechanics Improve sensi*vity of gravita*onal wave detectors

  • See QN, in especially

radia*on pressure noise in advance of large scale detector.

  • Develop the reduc*on

technique of quantum in table top experiment.

  • Leads to increasing of GW

event ra*o.

  • Realize entanglement

between the macroscopic mirror which can be seen!!

  • Test of quantum gravity

theory or objec*ve collapse theory.

  • Ul*mately, lead to jointed

theory of QM and GR.

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ICRR GW group seminar (Nov. 9th, 2017) 16

Op*cal levita*on

Study quantum noise in interferometers Test of macroscopic quantum mechanics Improve sensi*vity of gravita*onal wave detectors

  • See QN, in especially

radia*on pressure noise in advance of large scale detector.

  • Develop the reduc*on

technique of quantum in table top experiment.

  • Leads to increasing of GW

event ra*o.

  • Realize entanglement

between the macroscopic mirror which can be seen!!

  • Test of quantum gravity

theory or objec*ve collapse theory.

  • Ul*mately, lead to jointed

theory of QM and GR.

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ICRR GW group seminar (Nov. 9th, 2017) 17

Laser interferometer

  • Michelson interferometer (MI) is a device which

convert phase change to power change as a signal. = Phase fluctua*on generates signal (or noise).

Laser

Mirror mo*on (or Phase fluctua*on) MI output

Photo detector (PD) Suspended mirrors

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ICRR GW group seminar (Nov. 9th, 2017) 18

Quantum noise of GW detector

  • Quantum noise of laser interferometer
  • == QN is caused by vacuum fluctua*on induced

from signal port (= dark port).

Laser PD Vacuum fluctua*on

GW

Ponderomor*vely (= through mirror mo*on) squeezed vacuum fluctua*on

GW signal

Dark port Bright port

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ICRR GW group seminar (Nov. 9th, 2017) 19

Quantum noise of GW detector

  • QN of ordinary (“classical”) interferometers

Radia*on pressure noise ∝ Shot noise ∝

P↑ P↑ Good ← Sensi*vity→ Bad

Corresponding to mirror mo*on

Displacement sensi*vity [m/rtHz]

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ICRR GW group seminar (Nov. 9th, 2017) 20

Quantum noise of GW detector

  • QN of ordinary (“classical”) interferometers

with homodyne detec*on = quantum measurement technique

Improve sensi*vity!

SQL can be beaten!!

Displacement sensi*vity [m/rtHz]

Good ← Sensi*vity→ Bad

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SLIDE 21

ICRR GW group seminar (Nov. 9th, 2017) 21

Op*cal levita*on

Study quantum noise in interferometers Test of macroscopic quantum mechanics Improve sensi*vity of gravita*onal wave detectors

  • See QN, in especially

radia*on pressure noise in advance of large scale detector.

  • Develop the reduc*on

technique of quantum in table top experiment.

  • Leads to increasing of GW

event ra*o.

  • Realize entanglement

between the macroscopic mirror which can be seen!!

  • Test of quantum gravity

theory or objec*ve collapse theory.

  • Ul*mately, lead to jointed

theory of QM and GR.

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ICRR GW group seminar (Nov. 9th, 2017) 22

  • If we can prepare two mirrors whose mo*on

was dominated by quantum effect, the mirrors are entangled.

  • Then, we can start to test of macroscopic

quantum mechanics.

Macroscopic quantum mechanics

提案されている検証方法

2016/01/27 修士論文審査会

巨視的な物体では，直接二重スリット実験をする代わりに それに相当する実験をし，重ね合わせが生じるかどうか検証する。 への到達が必要条件

LASER

PD PD FI BS

  • com. mode
  • diff. mode
  • com. mode
  • com. mode
  • diff. mode
  • diff. mode

dark port bright port

PRM

Sing sour ⟩ ⟩ ⟩ ⟩ ⟩ ⟩ ⟩

SQLに到達した振動子 同相モードと差動モード の重ねあわせ状態を観測 基底状態の振動子 到達が必要 → 単一光子で励起 単一光子源 振動子の の重ねあわせ状態を観測

These mirrors are entangled!!

  • Com. and Diff. mode

is in super posi*on.

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ICRR GW group seminar (Nov. 9th, 2017) 23

Op*cal levita*on

  • So far, two types (or more?) of OLs for mg-

scale mirrors have been proposed.

tripod type sandwich type

  • Y. Kuwahara, Master thesis,

University of Tokyo (2016)

  • Y. Michimura+, Opt.

Express (2017)

  • G. Guccione+, PRL

(2013)

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ICRR GW group seminar (Nov. 9th, 2017) 24

Op*cal levita*on

  • So far, two types (or more?) of OLs for mg-

scale mirrors have been proposed.

tripod type sandwich type

  • Y. Kuwahara, Master thesis,

University of Tokyo (2016)

  • Y. Michimura+, Opt.

Express (2017)

  • G. Guccione+, PRL

(2013)

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ICRR GW group seminar (Nov. 9th, 2017) 25

Sandwich type op*cal levita*on

Sandwich type op4cal levita4on

  • Inser*ng a curved *ny mirror (~

1mg) between two op*cal cavi*es allows the *ny mirror to levitate stably.

  • Simpler method.
  • Quantum noise dominant

system can be achieved.

  • This is s*ll theore*cal proposal

[1]. Thus, we need experimental demonstra*on.

Schema*c of the sandwich type op*cal levita*on. [1] Y. Michimura et al., Opt. Express, 2017. Tiny mirror = levitated mirror gravity

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ICRR GW group seminar (Nov. 9th, 2017) 26

  • Ver*cal: op*cal spring
  • Horizontal: *lt of op*cal axes
  • Rota*on: gravity

Stability of SW op*cal levita*on

Ver*cal Horizontal Rota*on Opera*on

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ICRR GW group seminar (Nov. 9th, 2017) 27

  • Ver*cal: op*cal spring
  • Horizontal: *lt of op*cal axes
  • Rota*on: gravity

Stability of SW op*cal levita*on

Ver*cal Horizontal Rota*on Opera*on

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ICRR GW group seminar (Nov. 9th, 2017) 28

  • QN dominate system can be achieved.

Sensi*vity of SW op*cal levita*on

Parameters mirror mass: 1 mg Finesse: 100 Laser power: 40 W (lower), 10 W (upper)

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ICRR GW group seminar (Nov. 9th, 2017) 29

  • 1. Introduc*on
  • 2. Op*cal Levita*on
  • 3. Current status
  • 4. Summary

Outline

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ICRR GW group seminar (Nov. 9th, 2017) 30

  • Challenging points

– Tiny mg-scale mirror fabrica*on

  • Evalua*on of the *ny mirror property

– Demonstra*on of horizontal stability of the sandwich type op*cal levita*on – How to reach the actual levita*on – How to reduce all of the classical noises – and so on

Current status

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ICRR GW group seminar (Nov. 9th, 2017) 31

  • Challenging points

– Tiny mg-scale mirror fabrica*on

  • Evalua*on of the *ny mirror property

– Demonstra*on of horizontal stability of the sandwich type op*cal levita*on – How to reach the actual levita*on – How to reduce all of the classical noises – and so on

Current status

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ICRR GW group seminar (Nov. 9th, 2017) 32

Fabrica*on of the *ny mirror

  • Specs of *ny mirror

– mass: 1.6 mg (dia: 3 mm, thick: 0.1 mm) – RoC: 30 mm (Convex) – Reflec*vity: 0.9995

  • Although the fabrica*on is

challenging, 1.6 mg mirror has been delivered.

– However, the mirror without any lack is only

  • ne.
  • Evalua*on of the delivered

mirror property is also challenging and on going.

Picture of the mirror ater coa*ng. Only

  • ne of seven does not have any lack.
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ICRR GW group seminar (Nov. 9th, 2017) 33

  • We are trying to demonstrate

it with a torsion pendulum before the fully op*cal setup.

  • Restoring torque generated by

sandwich type configura*on will be measured.

  • Well sensi*ve torsion

pendulum has been made.

  • The setup is being constructed

in a vacuum chamber.

Principle demonstra*on

Sandwich type Horizontal

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ICRR GW group seminar (Nov. 9th, 2017) 34

  • We are now tes*ng each component which is

needed for sandwich type op*cal levita*on.

  • Ater the current components test, we will

integrate them.

  • Then, we will try to levitate the mirror
  • p*cally in the next fiscal year (FY2018).

Future plan

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ICRR GW group seminar (Nov. 9th, 2017) 35

  • 1. Introduc*on
  • 2. Op*cal Levita*on
  • 3. Current status
  • 4. Summary

Outline

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ICRR GW group seminar (Nov. 9th, 2017) 36

  • For the development of the QN

reduc*on technique in GW detectors and test of macroscopic QM, we are preparing sandwich type op*cal levita*on.

  • We are now tes*ng each

component.

  • We will try to levitate the mirror
  • p*cally in the next fiscal year

(FY2018).

Summary

Schema*c of the sandwich type op*cal levita*on.

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ICRR GW group seminar (Nov. 9th, 2017) 37

Appendix

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ICRR GW group seminar (Nov. 9th, 2017) 38

Setup

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ICRR GW group seminar (Nov. 9th, 2017) 39

  • In the macroscopic world, does quantum

mechanics hold?

  • We have not seen quantum effect, such as

super posi*on, in the macroscopic world.

  • If we can see macroscopic quantum effect, it

might lead to the jointed theory between QM and general rela*vity.

Macroscopic quantum mechanics